<?php
defined('BASE') or exit('Access Denied!');

/**
 * Obullo Framework (c) 2009.
 *
 * PHP5 MVC Based Minimalist Software.
 * 
 * @package         obullo       
 * @author          obullo.com
 * @copyright       Ersin Guvenc (c) 2009.
 * @filesource
 * @license
 */

Class CartException extends CommonException {}  
 
// ------------------------------------------------------------------------

/**
 * Shopping Cart Class
 *
 * @package       Obullo
 * @subpackage    Libraries
 * @category      Shopping Cart
 * @author        Ersin Guvenc
 * @link
 */
Class cart_CORE implements PHP5_Library {

    // These are the regular expression rules that we use to validate the product ID and product name
    public $product_id_rules    = '\.a-z0-9_-'; // alpha-numeric, dashes, underscores, or periods
    public $product_name_rules  = '\.\:\-_ a-z0-9'; // alpha-numeric, dashes, underscores, colons or periods
    
    public $_cart_contents    = array();

    private static $instance;
    
    public static function instance()
    {
       if(! (self::$instance instanceof self))
       {
            self::$instance = new self();
       } 
       
       return self::$instance;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Shopping Class Constructor
     *
     * The constructor loads the Session class, used to store the shopping cart contents.
     */        
    public function init($params = array())
    {    
        // Are any config settings being passed manually?  If so, set them
        $config = array();
        if (count($params) > 0)
        {
            foreach ($params as $key => $val)
            {
                $config[$key] = $val;
            }
        }

        loader::base_helper('session');
        
        sess_start($params);   
         
        // Grab the shopping cart array from the session table, if it exists
        if (sess_get('cart_contents') !== FALSE)
        {
            $this->_cart_contents = sess_get('cart_contents');
        }
        else
        {
            // No cart exists so we'll set some base values
            $this->_cart_contents['cart_total']  = 0;        
            $this->_cart_contents['total_items'] = 0;        
        }
    
        log_message('debug', "Cart Class Initialized");
    }

    // --------------------------------------------------------------------
    
    /**
     * Insert items into the cart and save it to the session table
     *
     * @access   public
     * @param    array
     * @return   bool
     */
    public function insert($items = array())
    {
        // Was any cart data passed? No? Bah...
        if ( ! is_array($items) OR count($items) == 0)
        {
            log_message('error', 'The insert method must be passed an array containing data.');
            return FALSE;
        }
                
        // You can either insert a single product using a one-dimensional array, 
        // or multiple products using a multi-dimensional one. The way we
        // determine the array type is by looking for a required array key named "id"
        // at the top level. If it's not found, we will assume it's a multi-dimensional array.
    
        $save_cart = FALSE;        
        if (isset($items['id']))
        {            
            if ($this->_insert($items) == TRUE)
            {
                $save_cart = TRUE;
            }
        }
        else
        {
            foreach ($items as $val)
            {
                if (is_array($val) AND isset($val['id']))
                {
                    if ($this->_insert($val) == TRUE)
                    {
                        $save_cart = TRUE;
                    }
                }            
            }
        }

        // Save the cart data if the insert was successful
        if ($save_cart == TRUE)
        {
            $this->_save_cart();
            return TRUE;
        }

        return FALSE;
    }

    // --------------------------------------------------------------------
    
    /**
     * Insert
     *
     * @access    private
     * @param    array
     * @return    bool
     */
    private function _insert($items = array())
    {
        // Was any cart data passed? No? Bah...
        if ( ! is_array($items) OR count($items) == 0)
        {
            log_message('error', 'The insert method must be passed an array containing data.');
            return FALSE;
        }
        
        // --------------------------------------------------------------------
    
        // Does the $items array contain an id, quantity, price, and name?  These are required
        if ( ! isset($items['id']) OR ! isset($items['qty']) OR ! isset($items['price']) OR ! isset($items['name']))
        {
            log_message('error', 'The cart array must contain a product ID, quantity, price, and name.');
            return FALSE;
        }

        // --------------------------------------------------------------------
    
        // Prep the quantity. It can only be a number.  Duh...
        $items['qty'] = trim(preg_replace('/([^0-9])/i', '', $items['qty']));
        // Trim any leading zeros
        $items['qty'] = trim(preg_replace('/(^[0]+)/i', '', $items['qty']));

        // If the quantity is zero or blank there's nothing for us to do
        if ( ! is_numeric($items['qty']) OR $items['qty'] == 0)
        {
            return FALSE;
        }
                
        // --------------------------------------------------------------------
    
        // Validate the product ID. It can only be alpha-numeric, dashes, underscores or periods
        // Not totally sure we should impose this rule, but it seems prudent to standardize IDs.
        // Note: These can be user-specified by setting the $this->product_id_rules variable.
        if ( ! preg_match("/^[".$this->product_id_rules."]+$/i", $items['id']))
        {
            log_message('error', 'Invalid product ID.  The product ID can only contain alpha-numeric characters, dashes, and underscores');
            return FALSE;
        }

        // --------------------------------------------------------------------
    
        // Validate the product name. It can only be alpha-numeric, dashes, underscores, colons or periods.
        // Note: These can be user-specified by setting the $this->product_name_rules variable.
        if ( ! preg_match("/^[".$this->product_name_rules."]+$/i", $items['name']))
        {
            log_message('error', 'An invalid name was submitted as the product name: '.$items['name'].' The name can only contain alpha-numeric characters, dashes, underscores, colons, and spaces');
            return FALSE;
        }

        // --------------------------------------------------------------------

        // Prep the price.  Remove anything that isn't a number or decimal point.
        $items['price'] = trim(preg_replace('/([^0-9\.])/i', '', $items['price']));
        // Trim any leading zeros
        $items['price'] = trim(preg_replace('/(^[0]+)/i', '', $items['price']));
        
        // Is the price a valid number?
        if ( ! is_numeric($items['price']))
        {
            log_message('error', 'An invalid price was submitted for product ID: '.$items['id']);
            return FALSE;
        }

        // --------------------------------------------------------------------
        
        // We now need to create a unique identifier for the item being inserted into the cart.
        // Every time something is added to the cart it is stored in the master cart array.  
        // Each row in the cart array, however, must have a unique index that identifies not only 
        // a particular product, but makes it possible to store identical products with different options.  
        // For example, what if someone buys two identical t-shirts (same product ID), but in 
        // different sizes?  The product ID (and other attributes, like the name) will be identical for 
        // both sizes because it's the same shirt. The only difference will be the size.
        // Internally, we need to treat identical submissions, but with different options, as a unique product.
        // Our solution is to convert the options array to a string and MD5 it along with the product ID.
        // This becomes the unique "row ID"
        if (isset($items['options']) AND count($items['options']) > 0)
        {
            $rowid = md5($items['id'].implode('', $items['options']));
        }
        else
        {
            // No options were submitted so we simply MD5 the product ID.
            // Technically, we don't need to MD5 the ID in this case, but it makes
            // sense to standardize the format of array indexes for both conditions
            $rowid = md5($items['id']);
        }        

        // --------------------------------------------------------------------

        // Now that we have our unique "row ID", we'll add our cart items to the master array
        
        // let's unset this first, just to make sure our index contains only the data from this submission
        unset($this->_cart_contents[$rowid]);        
        
        // Create a new index with our new row ID
        $this->_cart_contents[$rowid]['rowid'] = $rowid;
    
        // And add the new items to the cart array            
        foreach ($items as $key => $val)
        {
            $this->_cart_contents[$rowid][$key] = $val;
        }

        // Woot!
        return TRUE;
    }

    // --------------------------------------------------------------------
    
    /**
     * Update the cart
     *
     * This function permits the quantity of a given item to be changed. 
     * Typically it is called from the "view cart" page if a user makes
     * changes to the quantity before checkout. That array must contain the
     * product ID and quantity for each item.
     *
     * @access    public
     * @param    array
     * @param    string
     * @return    bool
     */
    public function update($items = array())
    {
        // Was any cart data passed?
        if ( ! is_array($items) OR count($items) == 0)
        {
            return FALSE;
        }
            
        // You can either update a single product using a one-dimensional array, 
        // or multiple products using a multi-dimensional one.  The way we
        // determine the array type is by looking for a required array key named "id".
        // If it's not found we assume it's a multi-dimensional array
        $save_cart = FALSE;
        if (isset($items['rowid']) AND isset($items['qty']))
        {
            if ($this->_update($items) == TRUE)
            {
                $save_cart = TRUE;
            }
        }
        else
        {
            foreach ($items as $val)
            {
                if (is_array($val) AND isset($val['rowid']) AND isset($val['qty']))
                {
                    if ($this->_update($val) == TRUE)
                    {
                        $save_cart = TRUE;
                    }
                }            
            }
        }

        // Save the cart data if the insert was successful
        if ($save_cart == TRUE)
        {
            $this->_save_cart();
            return TRUE;
        }

        return FALSE;
    }

    // --------------------------------------------------------------------
    
    /**
     * Update the cart
     *
     * This function permits the quantity of a given item to be changed. 
     * Typically it is called from the "view cart" page if a user makes
     * changes to the quantity before checkout. That array must contain the
     * product ID and quantity for each item.
     *
     * @access   private
     * @param    array
     * @return   bool
     */    
    private function _update($items = array())
    {
        // Without these array indexes there is nothing we can do
        if ( ! isset($items['qty']) OR ! isset($items['rowid']) OR ! isset($this->_cart_contents[$items['rowid']]))
        {
            return FALSE;
        }
        
        // Prep the quantity
        $items['qty'] = preg_replace('/([^0-9])/i', '', $items['qty']);

        // Is the quantity a number?
        if ( ! is_numeric($items['qty']))
        {
            return FALSE;
        }
        
        // Is the new quantity different than what is already saved in the cart?
        // If it's the same there's nothing to do
        if ($this->_cart_contents[$items['rowid']]['qty'] == $items['qty'])
        {
            return FALSE;
        }

        // Is the quantity zero?  If so we will remove the item from the cart.
        // If the quantity is greater than zero we are updating
        if ($items['qty'] == 0)
        {
            unset($this->_cart_contents[$items['rowid']]);        
        }
        else
        {
            $this->_cart_contents[$items['rowid']]['qty'] = $items['qty'];
        }
        
        return TRUE;
    }

    // --------------------------------------------------------------------
    
    /**
     * Save the cart array to the session DB
     *
     * @access    private
     * @return    bool
     */
    private function _save_cart()
    {
        // Unset these so our total can be calculated correctly below
        unset($this->_cart_contents['total_items']);
        unset($this->_cart_contents['cart_total']);

        // Lets add up the individual prices and set the cart sub-total
        $total = 0;
        foreach ($this->_cart_contents as $key => $val)
        {
            // We make sure the array contains the proper indexes
            if ( ! is_array($val) OR ! isset($val['price']) OR ! isset($val['qty']))
            {
                continue;
            }

            $total += ($val['price'] * $val['qty']);
            
            // Set the subtotal
            $this->_cart_contents[$key]['subtotal'] = ($this->_cart_contents[$key]['price'] * $this->_cart_contents[$key]['qty']);
        }

        // Set the cart total and total items.
        $this->_cart_contents['total_items'] = count($this->_cart_contents);            
        $this->_cart_contents['cart_total']  = $total;
    
        // Is our cart empty?  If so we delete it from the session
        if (count($this->_cart_contents) <= 2)
        {
            sess_unset('cart_contents');
            
            // Nothing more to do... coffee time!
            return FALSE;
        }

        // If we made it this far it means that our cart has data.
        // Let's pass it to the Session class so it can be stored
        sess_set(array('cart_contents' => $this->_cart_contents));

        // Woot!
        return TRUE;    
    }

    // --------------------------------------------------------------------
    
    /**
     * Cart Total
     *
     * @access    public
     * @return    integer
     */
    public function total()
    {
        return $this->_cart_contents['cart_total'];
    }

    // --------------------------------------------------------------------
    
    /**
     * Total Items
     *
     * Returns the total item count
     *
     * @access    public
     * @return    integer
     */
    public function total_items()
    {
        return $this->_cart_contents['total_items'];
    }

    // --------------------------------------------------------------------
    
    /**
     * Cart Contents
     *
     * Returns the entire cart array
     *
     * @access    public
     * @return    array
     */
    public function contents()
    {
        $cart = $this->_cart_contents;
        
        // Remove these so they don't create a problem when showing the cart table
        unset($cart['total_items']);
        unset($cart['cart_total']);
    
        return $cart;
    }

    // --------------------------------------------------------------------
    
    /**
     * Has options
     *
     * Returns TRUE if the rowid passed to this function correlates to an item
     * that has options associated with it.
     *
     * @access    public
     * @return    array
     */
    public function has_options($rowid = '')
    {
        if ( ! isset($this->_cart_contents[$rowid]['options']) OR count($this->_cart_contents[$rowid]['options']) === 0)
        {
            return FALSE;
        }
        
        return TRUE;
    }

    // --------------------------------------------------------------------
    
    /**
     * Product options
     *
     * Returns the an array of options, for a particular product row ID
     *
     * @access    public
     * @return    array
     */
    public function product_options($rowid = '')
    {
        if ( ! isset($this->_cart_contents[$rowid]['options']))
        {
            return array();
        }

        return $this->_cart_contents[$rowid]['options'];
    }

    // --------------------------------------------------------------------
    
    /**
     * Format Number
     *
     * Returns the supplied number with commas and a decimal point.
     *
     * @access    public
     * @return    integer
     */
    public function format_number($n = '')
    {
        if ($n == '')
        {
            return '';
        }
    
        // Remove anything that isn't a number or decimal point.
        $n = trim(preg_replace('/([^0-9\.])/i', '', $n));
    
        return number_format($n, 2, '.', ',');
    }
        
    // --------------------------------------------------------------------
    
    /**
     * Destroy the cart
     *
     * Empties the cart and kills the session
     *
     * @access    public
     * @return    null
     */
    public function destroy()
    {
        unset($this->_cart_contents);
    
        $this->_cart_contents['cart_total'] = 0;        
        $this->_cart_contents['total_items'] = 0;        

        sess_unset('cart_contents');
    }


}
// END Cart Class

/* End of file Cart.php */
/* Location: ./base/libraries/php5/Cart.php */
?>